Low frequency of delayed ischemic events on MRI after flow diversion for intracranial aneurysms

The rate of silent ischemia detected on Magnetic Resonance Imaging (MRI) in the long-term follow-up period following endovascular treatment of intracranial aneurysms with the Pipeline Embolization Device (PED) is not well established. The purpose of this study was to evaluate the occurrence rate of silent ischemia detected on MRI in patients undergoing treatment of intracranial aneurysms with PED receiving at least 6 months of MRI follow-up.We evaluated our institution's database of patients receiving PED treatment of intracranial aneurysms. Imaging records were searched to identify which patients received an MRI at least six-months postoperatively. MR images were reviewed for evidence of new infarction and medical records were reviewed to determine the clinical outcome.Of the 68 patients with MR imaging following aneurysm treatment with PED, 40 patients had an MRI at least six months following treatment with the PED. Of patients with MRI at ≥6 months following PED treatment, 2/40 (5.0%) had a new infarct. Of these, one had a lacunar infarct which was likely non-embolic and one patient had a punctate infarction in the contralateral centrum semiovale. None of these infarcts were symptomatic.In this study, a small number of silent ischemic events (5.0%) was found on routine long-term follow-up MRI of patients undergoing flow diversion. These events did not lead to any neurologic deficits. Our findings add to the available evidence on the long-term safety of flow diversion for the treatment of intracranial aneurysms.